1. Field of the Invention
The present invention relates generally to suspensions for supporting read/write heads over recording media. In particular, the present invention is head suspension assembly with a tracking microactuator.
2. Description of the Related Art
Magnetic disk drives include suspensions for supporting magnetic read/write heads over information tracks of rotating disks. The well known and widely used Watrous-type suspensions include a load beam having a baseplate on a proximal end, a flexure on a distal end, a relatively rigid region adjacent to the flexure and a spring region between the baseplate and rigid region. An air-bearing slider which includes the magnetic head is mounted to the flexure. The baseplate of the suspension is mounted to an actuator arm. A motor which is controlled by a servo control system rotates the actuator arm to position the magnetic head over desired information tracks on the magnetic disk.
Disk drive manufacturers continue to develop smaller yet higher storage capacity drives. Storage capacity increases are achieved in part by increasing the density of the information tracks on the magnetic disks (i.e., by using narrower and/or more closely spaced tracks). As track density increases, however, it becomes increasingly difficult for the motor and servo control system to quickly and accurately position the magnetic head over the desired servo track.
The use of microactuators or fine tracking motors has been proposed to overcome these problems. One such microactuator is disclosed in the Denny K. Miu et al. article, Silicon Microstructures and Microactuators for Compact Computer Disk Drives, IEEE Control Systems (December, 1994). This microactuator is machined from silicon and is positioned between the flexure and slider.
There is, however, a continuing need for improved microactuators. In particular, the microactuator must be capable of quickly and accurately positioning the magnetic head. The microactuator should be lightweight to minimize detrimental effects on the resonance characteristics of the suspension, and relatively thin to enable close disk-to-disk spacing. To be commercially viable the microactuator must also be reliable and capable of being efficiently manufactured.